1. Field of the Invention
This invention relates to hopper assemblies for receiving from a wagon or truck granular and/or grains dumped into a pit for storage or removal from the base of the pit while controlling and containing the dust during dumping.
2. Related Art
It is well-known for a material, such as grain or other granular forms, to be delivered to grain elevators by trucks or wagons that pour the contents into a receiving hopper connected to a pit larger than the truck for rapid unloading. Most materials, such as grain and other granular materials, produce dust or have dust associated with them and the dust rises from the bottom of the pit in large quantities when a load of grain or granular material is dumped into the pit which may be 25 feet in depth. This dust cloud is formed by the granular material hitting the bottom of the pit, the force of the material loosens the dust and also forces the air upwardly as the air in the pit is replaced by the solid material.
It has been found that such dust is detrimental to the health of operators and the farmers or deliverers, who are exposed to this excess dust as material is dumped into a pit. The Illinois EPA has found that such dust emissions must be controlled. This invention has been found by the Illinois EPA to control particulate matter and improve the opacity readings of the surrounding air when installed and operated in pit situations.
It has been found that if this system is properly installed, the Illinois Environmental Protection Agency will accept this system as an equivalent compliance system for control of particular matter emissions at a major dump pit area in accordance with Section 212,462(b)(2) of Title 35: Subtitle B, Chapt. 1 of the Illinois Pollution Control Board Rules and Regulations.
It has been proposed to solve this dust problem prior to this invention by extracting dust laden air from the hopper or pit through filters, but this system has never been satisfactory because of the size of the pits and the large volume flow of air, which must be extracted and filtered.
Other solutions, which have been proposed, include pivotly moving baffles of inverted "V" shaped cross-sections hanging under gravity, but these cross sections are subject to clogging thus jamming and permitting dust clouds to escape to the atmosphere.
Other solutions proposed have been to have an upwardly facing mouth and including, resiliently flexible baffles extending downward from a fixed horizontal extending top edge portion, to a free edge portion. Such a system is subject to failure when large amounts of material, such as coming from a truck loaded with grain, are dumped into the pit at a rapid rate.
According to this invention, the pit remains closed by a plurality of sections having a plurality of closed louvers covering the pit opening until a sufficient volume of material is loaded onto the metering section of the control system. When the material begins to flow, the flow is sensed by a sensor, which is adjustable to avoid false signals. A timing means is activated by the sensor, the timing means is also variable depending upon the rate of flow from the dumping vehicle. The time is set so that a substantial amount of grain or other material is on the louvers of the metering section before the metering section louvers are opened. This means that the metering section is choke loaded, i.e. the material is going into the solid mass preventing any air from escaping through the open metering section. All of the dump sections are closed and thus air and dust from the pit cannot escape into the general atmosphere. In as much as the metering section cannot completely handle the rate of dumping, material will spill or flow over and onto the dump sections even if the metering section is wide open.
This material that flows over onto the dump sections will be dumped later simultaneously and rapidly so that air and dust will not be able to escape from the pit. This dump section will open and close very rapidly, for example in 5 seconds.
Thus, the desirable characteristics of variable and controlled rates of flow and varied areas for filling the pit or dumping the grain are utilized to prevent the flow of dust from the pit to the ambient air.